1. Field of the Invention
The present invention relates in general to a door latch system which latches a door to a fixed member, and more particularly to a door latch operating device which operates the system to assume its door lock or door unlock condition.
2. Description of the Prior Art
In the field of the door latch operating device, there has been proposed a so-called dual knob type operating device which makes it difficult for a thief to open the door from outside. One of the conventional dual knob type operating devices is disclosed in U.S. Pat. No. 4,083,589, which comprises generally a first button slidably mounted in the door for vertical movement from its lowermost lock position to its uppermost unlock position, a second button slidably mounted in the door for horizontal movement from an outer inoperative position to an inner operative position, and a wedge body mounted on the second button and provided with an inclined surface which is slidably engaged with the first button to move it from the lowermost lock position to the uppermost unlock position, and vice versa.
However, since this conventional dual knob type operating device is constructed without taking a deeper consideration on compactness thereof, the device produced has a considerable thickness. Thus, upon assembly to the door, the device is considerably projected into the vehicle cabin thereby reducing the effective space of the same.